HELIX-LUCERNA. 109 



H. TRIDENTINA Ferussac. PL 35, figs. 22-26. 



Narrowly umbilicate or imperforate, depressed-trochoidal, solid 

 opaque, shining, whitish, with two brown bands and a sub-sutural 

 brown line ; upper surface suffused with yellowish brown ; surface 

 nearly smooth, the delicate incremental striae and granulation nearly 

 effaced ; spire conoidal, obtuse ; apex planulate ; sutures linear ,- 

 whorls 4i to 5, a little convex, the last more or less bluntly angular 

 at the periphery, flattened beneath, descending anteriorly, deeply 

 scrobiculate behind the peristome; aperture very oblique, transverse, 

 oblong-truncate ; peristome white or brown, expanded, reflexed, 

 expanded and adnate at the insertion, nearly or entirely covering 

 the umbilicus, the basal margin bearing inside three teeth, the twa 

 outer connected, arising from a common elevation. There is 

 sometimes a minute fourth tooth developed near the insertion of the 

 basal lip. Parietal wall with a light translucent callus. 



Alt. 13-14, diam. 25 mill. 



Jamaica* 



H. tridentina FEB., Histoire t. 54A, f. 4-6. PFR. Symb. ii, p. 143 ; 

 Monogr. i, p.. 283; Conchyl. Cab., p. 65, t. 78, f. 1, 2. PHILIPPI, 

 Abbild., ii, p. 186, Helix t. 9, f. 8. H. swainsoniana C. B. AD., 

 Contrib. to Conch., No. 9, p. 169. PFR. Monogr. iii, p. 260. 

 H. browmana PFR. Mai. Blat. i-x, p. 152 (1862) ; Novit. Conch, i, 

 p. 214, t. 57, f. 1-3. 



This shell is more or less bluntly carinated; it is often more 

 depressed than my figures, and as frequently more elevated. The 

 umbilicus is nearly, sometimes wholly, covered by the expansion of 

 the basal lip. The cuticle often show r s alternating streaks of white 

 and yellowish. These streaks are not so well defined as fig. 24 

 shows, but are irregular, zig-zag. There is a variety in which the 

 upper band extends to the suture, and the lower to the center of the 

 base (fig. 26). The following form is scarcely separable, even as a 

 variety. 



Var. BROWNEANA Pfr. PI. 35, figs. 19-21. 



Depressed, imperforate, obtusely carinated ; body-whorl with a 

 narrow brown band on the base, and a broad one above, beneath 

 the suture ; lip typically white, basal margin with four teeth, the 

 inner one quite small. Alt. 11, diam. 23? mill. 



